chenodeoxycholic acid

Chenodeoxycholic acid (also known as chenodesoxycholic acid, chenocholic acid and 3α,7α-dihydroxy-5β-cholan-24-oic acid) is a bile acid. It occurs as a white crystalline substance insoluble in water but soluble in alcohol and acetic acid, with melting point at 165-167°C. Salts of this carboxylic acid are called chenodeoxycholates. Chenodeoxycholic acid is one of the main bile acids produced by the liver.
It was first isolated from the bile of the domestic goose, which gives it the "cheno" portion of its name (Greek: χήν = goose).
Chenodeoxycholic acid and cholic acid are the two primary bile acids in humans. Some other mammals have muricholic acid or deoxycholic acid rather than chenodeoxycholic acid.
Chenodeoxycholic acid is synthesized in the liver from cholesterol by a process which involves several enzymatic steps. Like other bile acids, it can be conjugated in the liver with taurine or glycine, forming taurochenodeoxycholate or glycochenodeoxycholate. Conjugation results in a lower pKa. This means the conjugated bile acids are ionized at the usual pH in the intestine and will stay in the gastrointestinal tract until reaching the ileum where most will be reabsorbed. Bile acids form micelles which facilitate lipid digestion. After absorption, they are taken up by the liver and resecreted, so undergoing an enterohepatic circulation. Unabsorbed chenodeoxycholic acid can be metabolised by bacteria in the colon to form the secondary bile acid known as lithocholic acid.
Choendeoxycholic acid is the most potent natural bile acid at stimulating the nuclear bile acid receptor, farnesoid X receptor (FXR). The transcription of many genes is activated by FXR.